// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/views/controls/image_view.h"

#include <utility>

#include "base/logging.h"
#include "base/strings/utf_string_conversions.h"
#include "third_party/skia/include/core/SkPaint.h"
#include "ui/accessibility/ax_view_state.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/geometry/insets.h"
#include "ui/views/painter.h"

namespace views {

namespace {

    // Returns the pixels for the bitmap in |image| at scale |image_scale|.
    void* GetBitmapPixels(const gfx::ImageSkia& img, float image_scale)
    {
        DCHECK_NE(0.0f, image_scale);
        const SkBitmap& bitmap = img.GetRepresentation(image_scale).sk_bitmap();
        SkAutoLockPixels pixel_lock(bitmap);
        return bitmap.getPixels();
    }

} // namespace

// static
const char ImageView::kViewClassName[] = "ImageView";

ImageView::ImageView()
    : image_size_set_(false)
    , horiz_alignment_(CENTER)
    , vert_alignment_(CENTER)
    , interactive_(true)
    , last_paint_scale_(0.f)
    , last_painted_bitmap_pixels_(NULL)
    , focus_painter_(Painter::CreateDashedFocusPainter())
{
}

ImageView::~ImageView()
{
}

void ImageView::SetImage(const gfx::ImageSkia& img)
{
    if (IsImageEqual(img))
        return;

    last_painted_bitmap_pixels_ = NULL;
    gfx::Size pref_size(GetPreferredSize());
    image_ = img;
    if (pref_size != GetPreferredSize())
        PreferredSizeChanged();
    SchedulePaint();
}

void ImageView::SetImage(const gfx::ImageSkia* image_skia)
{
    if (image_skia) {
        SetImage(*image_skia);
    } else {
        gfx::ImageSkia t;
        SetImage(t);
    }
}

const gfx::ImageSkia& ImageView::GetImage() const
{
    return image_;
}

void ImageView::SetImageSize(const gfx::Size& image_size)
{
    image_size_set_ = true;
    image_size_ = image_size;
    PreferredSizeChanged();
}

gfx::Rect ImageView::GetImageBounds() const
{
    gfx::Size image_size = GetImageSize();
    return gfx::Rect(ComputeImageOrigin(image_size), image_size);
}

void ImageView::ResetImageSize()
{
    image_size_set_ = false;
}

void ImageView::SetFocusPainter(scoped_ptr<Painter> focus_painter)
{
    focus_painter_ = std::move(focus_painter);
}

gfx::Size ImageView::GetPreferredSize() const
{
    gfx::Size size = GetImageSize();
    size.Enlarge(GetInsets().width(), GetInsets().height());
    return size;
}

bool ImageView::IsImageEqual(const gfx::ImageSkia& img) const
{
    // Even though we copy ImageSkia in SetImage() the backing store
    // (ImageSkiaStorage) is not copied and may have changed since the last call
    // to SetImage(). The expectation is that SetImage() with different pixels is
    // treated as though the image changed. For this reason we compare not only
    // the backing store but also the pixels of the last image we painted.
    return image_.BackedBySameObjectAs(img) && last_paint_scale_ != 0.0f && last_painted_bitmap_pixels_ == GetBitmapPixels(img, last_paint_scale_);
}

gfx::Size ImageView::GetImageSize() const
{
    return image_size_set_ ? image_size_ : image_.size();
}

gfx::Point ImageView::ComputeImageOrigin(const gfx::Size& image_size) const
{
    gfx::Insets insets = GetInsets();

    int x;
    // In order to properly handle alignment of images in RTL locales, we need
    // to flip the meaning of trailing and leading. For example, if the
    // horizontal alignment is set to trailing, then we'll use left alignment for
    // the image instead of right alignment if the UI layout is RTL.
    Alignment actual_horiz_alignment = horiz_alignment_;
    if (base::i18n::IsRTL() && (horiz_alignment_ != CENTER))
        actual_horiz_alignment = (horiz_alignment_ == LEADING) ? TRAILING : LEADING;
    switch (actual_horiz_alignment) {
    case LEADING:
        x = insets.left();
        break;
    case TRAILING:
        x = width() - insets.right() - image_size.width();
        break;
    case CENTER:
        x = (width() - image_size.width()) / 2;
        break;
    default:
        NOTREACHED();
        x = 0;
        break;
    }

    int y;
    switch (vert_alignment_) {
    case LEADING:
        y = insets.top();
        break;
    case TRAILING:
        y = height() - insets.bottom() - image_size.height();
        break;
    case CENTER:
        y = (height() - image_size.height()) / 2;
        break;
    default:
        NOTREACHED();
        y = 0;
        break;
    }

    return gfx::Point(x, y);
}

void ImageView::OnFocus()
{
    View::OnFocus();
    if (focus_painter_.get())
        SchedulePaint();
}

void ImageView::OnBlur()
{
    View::OnBlur();
    if (focus_painter_.get())
        SchedulePaint();
}

void ImageView::OnPaint(gfx::Canvas* canvas)
{
    View::OnPaint(canvas);
    OnPaintImage(canvas);
    Painter::PaintFocusPainter(this, canvas, focus_painter_.get());
}

void ImageView::GetAccessibleState(ui::AXViewState* state)
{
    state->role = ui::AX_ROLE_IMAGE;
    state->name = tooltip_text_;
}

const char* ImageView::GetClassName() const
{
    return kViewClassName;
}

void ImageView::SetHorizontalAlignment(Alignment ha)
{
    if (ha != horiz_alignment_) {
        horiz_alignment_ = ha;
        SchedulePaint();
    }
}

ImageView::Alignment ImageView::GetHorizontalAlignment() const
{
    return horiz_alignment_;
}

void ImageView::SetVerticalAlignment(Alignment va)
{
    if (va != vert_alignment_) {
        vert_alignment_ = va;
        SchedulePaint();
    }
}

ImageView::Alignment ImageView::GetVerticalAlignment() const
{
    return vert_alignment_;
}

void ImageView::SetTooltipText(const base::string16& tooltip)
{
    tooltip_text_ = tooltip;
}

base::string16 ImageView::GetTooltipText() const
{
    return tooltip_text_;
}

bool ImageView::GetTooltipText(const gfx::Point& p,
    base::string16* tooltip) const
{
    if (tooltip_text_.empty())
        return false;

    *tooltip = GetTooltipText();
    return true;
}

bool ImageView::CanProcessEventsWithinSubtree() const
{
    return interactive_;
}

void ImageView::OnPaintImage(gfx::Canvas* canvas)
{
    last_paint_scale_ = canvas->image_scale();
    last_painted_bitmap_pixels_ = NULL;

    if (image_.isNull())
        return;

    gfx::Rect image_bounds(GetImageBounds());
    if (image_bounds.IsEmpty())
        return;

    if (image_bounds.size() != gfx::Size(image_.width(), image_.height())) {
        // Resize case
        SkPaint paint;
        paint.setFilterQuality(kLow_SkFilterQuality);
        canvas->DrawImageInt(image_, 0, 0, image_.width(), image_.height(),
            image_bounds.x(), image_bounds.y(), image_bounds.width(),
            image_bounds.height(), true, paint);
    } else {
        canvas->DrawImageInt(image_, image_bounds.x(), image_bounds.y());
    }
    last_painted_bitmap_pixels_ = GetBitmapPixels(image_, last_paint_scale_);
}

} // namespace views
